Apparatus and process for chilling food products

Abstract: Apparatus and method for chilling a food product (4) which includes a food distribution device (12) having a pair of circular members (16, 18) including at least one spaced-apart partition (20) defining a food receiving area; the circular members (16, 18) rotating to cause food delivered to the food product receiving area to fall into a food storage compartment (10) in a uniform manner; and a cryogen releasing device (60) connected to one of the circular members which uniformly distributes a cryogenic substance to the food product within the food storage compartment (10).

Description: The present invention is generally directed to a device for chilling a food product in which the food product is uniformly distributed within a food receiving vessel while simultaneously being uniformly treated with a cryogenic substance to effect cooling. Commercial procedures for treating freshly killed poultry or meat generally require that the temperature of the fresh killed product be reduced in accordance with standards established by the United States Department of Agriculture (USDA). Conventionally, the fresh killed product is treated with brine to lower the temperature of the food product to about 7 o C (about 45°F). This procedure reduces water loss in the product, prevents the growth of bacteria and extends the shelf life of the food product. The brine treated product is then cut and/or ground as desired prior to packaging. The cutting/ grinding step generates heat thereby increasing the temperature of the food product. Prior to packaging the food product, however, it is necessary to lower the temperature of the food product in the range of from about -1 o C to 4.5 o C (about 30 to 40°F). Conventional methods of chilling the food product after it has been cut/ground and treated with brine involve manual operations. Specifically, the food product is placed in a large, often times rectangular vessel. Dry ice in the form of pellets is shoveled into the vessel to lower the temperature of the food product to meet USDA requirements. Such manual systems, however, are inefficient and inconsistent. The shoveling of dry ice into the receiving vessel often produces localised cold spots so that a portion of the food product is chilled to lower than necessary temperatures while other portions of the food product remain above desired temperatures. To date, there is no apparatus or method which uniformly distributes the food product within the storage vessel and uniformly treats the food product with a coolant as it is distributed within the vessel. EP-A-0422280 discloses the cooling and/or freezing of foodstuffs in a process in which they are placed in a cooling chamber into which liquefied gas is sprayed, initially so as to bring the surface layers of the product to their freezing point, and the product is then allowed to cool freely until its centre reaches a similar level. More gas is then introduced to cool the product further. It would be a significant advance in the art of chilling food products, if the food product can be uniformly distributed within the food receiving vessel while receiving a uniform distribution of a coolant. The present invention therefore provides an apparatus for chilling a food product comprising a food storage compartment for storing the food product at rest and means for cooling the food product therein, characterised in that the food storage compartment receives the food product while in motion from a food distribution means; the food distribution means are operatively engaged to the top of the food storage compartment for receiving the food product from a source and for uniformly distributing the food product within the food storage compartment; and means are provided for uniformly distributing a coolant to cool the food product while the food product is contained within the food storage compartment. In a second aspect, the invention also provides a method of chilling a food product with a coolant characterised by the steps of delivering a food product to an upper surface of a first circular member having an opening therein, said opening adapted to receive the food product and deliver the food product to a food storage vessel; rotating the first circular member; rotating a second circular member in a non-congruent manner with respect to said first circular member; said second circular member, comprising at least one partition, together with the first circular member forming at least one food receiving area on the surface of the first circular member; said second circular member being rotated in a manner so that the partitions contact the food product in said food receiving portions and urge the food product into said opening; and adding a coolant to the food storage vessel in uniform distribution to cool the food product therein. The present invention is generally directed to an apparatus and process for chilling a food product. The apparatus comprises a food distribution means for delivering the food product in a uniform manner to a food storage compartment. The food distribution means is operatively engaged at the top of the food storage compartment and serves the function of uniformly distributing the food product within the food storage compartment. On the underside of the food distribution means is a cryogen releasing means. The cryogen releasing means releases a cryogenic substance onto the food product in a uniform manner as the food product is uniformly distributed within the food storage compartment. As a consequence of the present invention, the food storage compartment receives a uniform distribution of the food product which in turn is uniformly cooled to USDA standards without localised cold spots brought about by uneven coolant distribution. The following drawings in which like reference characters indicate like parts are illustrative of embodiments of the invention and are not intended to limit the invention as encompassed by the claims forming part of the application. Figure 1 is a perspective view of an embodiment of the invention for chilling a food product received from a conveyor; Figure 2 is a perspective view of the food distribution means associated with the top of the food storage compartment for receiving the food product and for distributing the food product uniformly within the food storage compartment; Figure 3 is a side view of an embodiment of the cryogen releasing means for uniformly distributing a cryogenic substance into the food storage compartment as food is released through the opening of the food distribution means; and Figure 4 is a side view of another embodiment of the cryogen releasing means. The present invention is directed to an apparatus and a process for chilling food products, particular meat and poultry, in an efficient and uniform manner. The present device receives the food product from a source such as a conveyer belt and through a unique food distribution means distributes the food product within a food storage compartment in a uniform manner. Coupled to the food distribution means, in accordance with another aspect of the present invention, is a cryogen releasing means which releases a cryogenic substance in a manner which eliminates cold spots and uniformly cools the food product loaded within the food storage compartment by the food distribution means. Referring to Figures 1 and 2, the apparatus for chilling a food product is shown generally by numeral 2. The food product 4, such as cut meat and/or poultry, is delivered to the chilling apparatus 2 by a conventional means such as a conveyor belt 6. The apparatus generally includes a storage compartment 10 for receiving the food product 4 and a food distribution device 12 which receives the food product 4 from the conveyor belt 6 and distributes the food product uniformly within the storage compartment 10 as explained hereinafter. The food distribution device 12 includes a base 14, a first circular member 16 and a second circular member 18 as shown specifically in Figure 2. The second circular member 18 includes at least one, preferably a plurality of spaced-apart partitions 20 (four partitions are shown) which together with the upper surface 22 of the first circular member 16 form a corresponding number of food receiving areas 24.The upper surface 22 of the first circular member 16 has an opening 26 therein which is of sufficient size to enable the food product 4 to pass therethrough and into the storage compartment 10. The first circular member 16 and the second circular member 18 rotate in a non-congruent manner. That is, for example, the second circular member 18 may either rotate at a different speed than the first circular member 16 and/or rotate in different direction than the first circular member 16. The rotation of the respective circular members 16,18 in a non-congruent manner is designed to urge the food product 4 which is received in the food receiving areas 24 into the opening 26 by the partitions 20. The relationship between the first circular member 16 and the second circular member 18 is best shown by reference to Figure 2. When the food product 4 is received within a food receiving area 24a, the partitions 20a and 20b which border the food receiving area 24a rotate in a non-congruent manner such as by rotating at a speed greater than that of the first circular member 16. Accordingly, the food product is caused to move across the upper surface 22 of the first circular member 16 until the food product reaches the opening 26 and falls into the storage compartment 10. As previously indicated, the same results can be achieved by reversing the rotation of the second circular member 18 with respect to the first circular member 16. Rotation of the first and second circular members 16,18 may be accomplished by a gear driving mechanism having respective gear wheels which engage the outer rim of the respective circular members. Referring to Figure 2, there is shown the first circular member 16 having an outside edge 28 composed of gear teeth 30. The second circular member 18 has a corresponding outside edge 32 composed of similar gear teeth 34. The gear teeth 34 of the second circular member 18 are engaged by a first gear drive 36 comprising a motor 38 and a gear wheel 40. In operation, the rotation of the gear wheel 40 causes the first circular member 16 to rotate in a like manner at a set speed. A similar gear drive 42 comprising a motor 44 and corresponding gear wheel 46 is provided for the first circular member 16 which causes the first circular member 16 to rotate at a desired speed. In one embodiment of the invention the gear wheel 40 causes the second circular member 18 to rotate at a rate of speed different than that of the first circular member 16. In another embodiment of the invention, the gear wheel 40 may be caused to rotate in a direction opposite to that of the corresponding gear wheel 46 which controls movement of the first circular member 16. Accordingly, the food product which enters the food receiving area 24 will be contacted by a partition 20 bordering the food receiving area 24 and pushed along the surface 22 of the first circular member 16. Eventually, the food product 4 will be urged into the opening 26 and deposited within the storage compartment 10. Gear drive 40 may be provided with respective ratchet clutches (not shown), known in the art, (e.g. model #400 manufactured by MAYR). The ratchet clutch serves to stop the motion of the second circular member 18 when the food product 4 is lodged between one of the partitions 20 and the side of the opening 26 in the upper surface 22 of the first circular member 16. This optional device is provided to prevent damage to the apparatus on the rare occasion when the food product 4 may become lodged between the first and the second circular members 16 and 18. The food distribution device 12 may also be optionally provided with one or more, preferably three, guide wheels 48 which provide support for the first circular member 16. Each guide wheel 48 has an outer rim 50 which rotates and engages the outside edge 28 of the first circular member 16 to assure that the first circular member 16 rotates smoothly when in operation. The food distribution system described above effectively transports the food product 4 through the opening 26 at spaced-apart intervals thereby distributing the food product 4 within the storage compartment 10 in a uniform manner. As a consequence, the food product 4 is evenly distributed throughout the entire volume of the storage compartment 10. In another aspect of the present invention, there is provided a unique cooling device which relies on a cryogenic substance to cool the food product contained within the food storage compartment. A cryogen releasing device is attached to the underside of the first circular member and releases a cryogenic substance as the first circular member is rotated above the storage compartment. Referring to Figures 1-3, there is disclosed a cryogen releasing device 60 shown affixed to the underside of first circular member 16. The cryogen releasing device 60 is shown proximate to the opening 26 in the first circular member 16. It should be noted, however, that the cryogen releasing device 60 may be positioned anywhere along the underside of the first circular member 16. The cryogen releasing device 60 includes a first conduit 62 and a second conduit 64 which are connected together by a coupling device 66. The second conduit 64 is connected to a source of cryogen (not shown). The first conduit 62 which extends upwards through the first and second circular members 16, 18 is connected to at least one device for releasing the cryogenic substance in the desired form for cooling. As shown in Figures 3 and 4, when the cryogenic substance is carbon dioxide, at least one cone-shaped generator 68 is provided for forming solid flakes of carbon dioxide and releasing the flakes of carbon dioxide onto the food product contained within the vessel. The solid flakes of carbon dioxide are formed in a conventional manner. More specifically, carbon dioxide is generally shipped and stored in pressure vessels at 2.4 Gpa (300 psig) and -18 o C (0°F), in liquid form. When cooling is needed, it is transferred via a pipe to an orifice. Upon injection through an orifice, the liquid changes state to a solid and gas at atmospheric conditions. The amount of solid formed is approximately 43%. The shape of the snow cones or snow generators 68 concentrate the solid carbon dioxide particles forcing them to collide and form larger particles referred to as snow. This snow then contacts the product to be cooled and sublimates giving up its cooling capacity. The cryogenic substance is released through the cones 68 as the cryogen releasing device is rotated in accordance with the rotation of the first circular member 16. In an alternative embodiment of the invention, the cryogenic substance may be a liquid, such as liquid nitrogen. The first conduit 62 is provided with a series of spaced-apart openings 70 as shown in Figure 4 to allow the liquid nitrogen to drip onto the food product within the storage compartment. Exhaust cryogen is released from the storage vessel through an exhaust port 74 as shown in Figure 1. The flow of the cryogenic substance to the cryogen releasing device 60 is controlled by a valve arrangement 72 shown generally in Figure 1. The flow of the cryogenic substance may be controlled by adjusting the valve arrangement 70 to limit the amount of cryogenic substance entering the second conduit 64 to a percentage of the total flow capacity. For example, if the conduit 64 is capable of handling 22.7 kg (50 pounds) per minute of the cryogenic substance (e.g. carbon dioxide or nitrogen) at full production, then the valve 70 could be set at 50% open if only 11.3 kg (25 pounds) per minute of flow are needed. Alternatively, the valve arrangement 70 can be turned on and off at spaced-apart intervals. As a result, the valve will be opened a percentage of the time and closed the remaining time. For example, if 22.7 kg (50 pounds) per minute of the cryogenic substance represented full capacity and only 75% of full capacity were desired, the valve arrangement 70 could be set in the open position for 45 seconds and in the closed position for 15 seconds by a conventional timing device (not shown). EXAMPLE 1 A storage compartment capable of housing approximately 1000 kg (2200 pounds) of meat or poultry is employed for receiving the food product from a conveyor as shown in Figure 1. The food product is supplied at a rate sufficient to fill the storage compartment in approximately fifteen minutes. The temperature of the food product entering the chilling apparatus is approximately 7 o C (45°F) and the temperature of the food product within the storage compartment is required to be about 2 o C (35°F). Employing turkey as an example, which has a specific heat of about 0.2 kWh/kg o C (0.8 Btu/lb.°F), requires the removal of 17600 kW (17,600 Btu) in fifteen minutes corresponding to approximately 70,400 kWh (70,400 Btu/hr). In order to remove this amount of heat, the apparatus as shown in Figure 1 is supplied with liquid carbon dioxide which removes heat at the rate of 51.2 kWh/kg (113 Btu/lb). Since the removal of 70,400 kW (70,400 Btu/hr) is equivalent to 1173 kW (1173 Btu per minute), approximately 4.7 kg (10.4 lbs). of liquid carbon dioxide must be supplied to the storage vessel per minute in order to reduce the temperature of the turkey product from 7 o C to 2 o C (45°F to 35°F). EXAMPLE 2 The same apparatus as described in Example 1 was employed for cooling turkey except that liquid nitrogen was used as the cryogenic substance with the cryogen releasing device shown in Figure 4. Since liquid nitrogen removes heat at the rate of 85.6 kW (85.6 Btu per minute), 6.2 kg (13.7 lbs). of liquid nitrogen per minute would be required to reduce the temperature of the turkey product from 7 o C to 2 o C (45°F to 35 °F).

Claims: Apparatus (2) for chilling a food product (4) comprising a food storage compartment (10) for storing the food product (4) at rest and means for cooling the food product (4) therein, wherein (a) the food storage compartment (10) receives the food product (4) while in motion from a food distribution means (12); (b) the food distribution means (12) are operatively engaged to the top of the food storage compartment (10) for receiving the food product (4) from a source (6) and for uniformly distributing the food product (4) within the food storage compartment (10); and (c) means (60) are provided for uniformly distributing a coolant to cool the food product (4) while the food product is contained within the food storage compartment (10). Apparatus as claimed in Claim 1 characterised in that the means (60) for cooling the food product comprises a cryogen releasing means (60) operatively engaged to the underside (16) of the food distribution means for uniformly releasing a cryogenic substance onto the food product (4) as the food product (4) is uniformly distributed within the food storage compartment to thereby cool the food product (4). Apparatus as claimed in Claim 2 characterised in that the cryogen releasing means comprises a conduit (64) affixed to a lower surface of the first circular member (16) and connected to a source of a cryogenic substance (68), and a releasing means (72) operatively connected to the conduit for releasing the cryogenic substance as the first circular member (16) is rotated. An apparatus as claimed in any of Claims 1 to 3 wherein the food distribution means (12) comprises: (a) a first circular member (16) having an upper and lower surface (22, 24)and an opening (26) therein sufficient for the food product to pass therethrough; (b) means (46) for rotating the first circular member; (c) a second circular member (18) positioned above the first circular member (16) comprising at least one partition (20) and together with the upper surface (22) of the first circular member (16) forming at least one food receiving area on the upper surface (22) of the first circular member; (d) means (40) for rotating the second circular member (18) in a non-congruent manner with respect to the first circular member (16); whereby the food product (4) which is placed on the upper surface (22) of the first circular member is caused to fall through the opening (26) in the first circular member into the food storage compartment (10) when one of said partitions (20a) contacts the food product (4) and urges said food product (4) into said opening (26). An apparatus as claimed in Claim 4 characterised in that the means (46) for rotating the first circular member (16) rotates the first circular member (16) at a speed different than that of the second circular member (18). An apparatus as claimed in Claim 4 or Claim 5 characterised in that the means (46) for rotating the first circular member (16) rotates the first circular member (16) in a different direction than the second circular member (18). A method of chilling a food product with a coolant comprising the steps of: (a) delivering a food product to an upper surface of a first circular member having an opening therein, said opening adapted to receive the food product and deliver the food product to a food storage vessel; b) rotating the first circular member; (c) rotating a second circular member in a non- congruent manner with respect to said first circular member; said second circular member, comprising at least one partition, together with the first circular member forming at least one food receiving area on the surface of the first circular member; said second circular member being rotated in a manner so that the partitions contact the food product in said food receiving portions and urge the food product into said opening; and (d) adding a coolant to the food storage vessel in uniform distribution to cool the food product therein. A method as claimed in Claim 7 wherein the step of adding a coolant to the food storage compartment comprises releasing a cryogenic substance from the first circular member into the food storage compartment as the first circular member is rotated. A method as claimed in Claim 8 wherein the cryogenic substance is released in the form of solid flakes. A method as claimed in Claim 8 wherein the cryogenic substance is released in the form of a liquid.

Inventors: APPOLONIA JOHN, BODDAERT ROBERT, MCCORMICK STEVE, APPOLONIA, JOHN, BODDAERT, ROBERT, MCCORMICK, STEVE
Applicants: BOC GROUP INC, THE BOC GROUP, INC.
Application year: 1994
Main classification: A23L3
IPC codes: F25D3, A23B4, A23L3